arnaud.pele@LIGO.ORG - posted 15:16, Friday 23 May 2014 - last comment - 10:32, Saturday 24 May 2014(12059)
IOP WD still looking at osem DC values
After the PSL went down, MC2 IOP watchdogs tripped this afternoon, which cascaded to HAM2/HAM3 ISIs.
It tripped because of a large ISC length control offset signal applied on the left and right osems of the top mass.
Similarly as what Jeff did on the sus WD models (cf his alog), the trigger on DC osem values in the iop models (upper path of screenshot) should be removed to avoid this kind of situations.
This could be done during the vent period in two weeks.
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The vent period would be an excellent time for me to upgrade the IOP models to the targeted SUS/SEI watchdog system. In that system the DC component of the OSEMs is only monitored.